The present invention relates to a piano hammer of the type used in the mechanical action of any type of piano, be it a grand piano (“pianoforte”) or an upright piano. More particularly, the invention relates to a covering on the striking surface of a piano hammer which results in improved tone quality, increased dynamic range and improved durability of the hammer.
One of the critical operating components of the mechanical action in a piano is the hammer that strikes the wire or wires of the piano string. Since the tone quality of each note in a piano is dependent upon the construction and density of the hammer, many attempts have been made to improve the hammer and especially its contact surface.
A piano hammer conventionally comprises an elongate “hammer head”, usually made of wood, having a nose portion that is usually wedge shaped. A felt covering surrounds the nose portion with tail portions affixed to the side surfaces of the nose portion, usually with glue and a reinforcing staple. Such felt covering defines a substantially elliptical peripheral surface which extends from the top of the hammer, in the region which strikes the piano string, away from this region through a widest point between the front and back of the hammer, hereinafter called the “equator” of the hammer, to the terminus of the tail portions. (It will be understood that the “top”, “front” and “back” of the hammer refer to the respective sides of a hammer as installed in a grand piano. This terminology will be used herein although the hammer may be installed in an upright piano where the “top” becomes the “front” of the hammer and the “front” and “back” become the “bottom” and “top”, respectively). Over time, the felt covering generally becomes worn and/or compressed and hardened at the top region under continuous use to such an extent as to impair the tone of the piano. Attempts have therefore been made to find a felt covering material which is highly resistant to wear and other damage.
The U.S. Pat. No. 3,487,429 to Johnson discloses a piano hammer having the felt covering forming the striking member comprised of a blend of wool fibers and thermoplastic fibers. This felt covering is said to be durable and can be formed with a “controlled density” for different registers of the piano.
The U.S. Pat. No. 4,135,430 to Hayashida discloses a simplified piano hammer comprising a wooden base, a striking head and an outer “protective covering” surrounding the end of the wooden base and covering the striking head. The striking head is a relatively thin strip made of elastic material such as polyurethane. The protective covering is made of a “protective material such as deer-skin or artificial leather”.
The U.S. Pat. No. 5,125,310 to Lombino teaches a piano hammer comprising an elongate wooden head with a “nose portion” and a felt body extending about the nose portion. Tail portions of the felt body are affixed to the side surfaces of the nose portion. The felt body is comprised of an “outer felt” made of 100% wool and an “under felt”. The patent is directed to a method of manufacturing wherein the sides of the outer felt are impregnated with an aqueous solution containing an acrylic copolymer.